Combing of textile fibres



Sept. 25, 1962 D. TAYLOR COMBING OF TEXTILE FIBRES Filed April 25, 195806' United States Patent 3,055,059 COMBING 0F TEXTILE FIBRES DonaldStuart Taylor, Belmont, Geelong, Victoria, Australia, assignor toCommonwealth Scientific and Industrial Research Organization, EastMelbourne, Victoria, Australia, a corporation of Australia Filed Apr.25, 1958, Ser. No. 731,032

Claims priority, application Australia May 3, 1957 4 Claims. (Cl.19--123) This invention relates to the combing of textile fibres.

In the processing of wool fibres, after the fibres have been passedthrough the backwash and gilling stages or other stages of preliminarypreparation, they are passed through a comb to further align the fibresand to separate the long fibres from the short fibres and also to removevegetable matter from the fibres. The sliver which emerges from the combis referred to as top" sliver and the short fibres, vegetable matter,neps etc. left behind is referred to as noil. Combs most commonly usedin textile mills using the Bradford" system are of the type known as theNoble comb. These comprise broadly a large circle of upstanding pins andtwo smaller circles of pins located within the large circle anddiametrically opposite one another. The large circle is rotatablymounted and carries around its periphery a number of balls of slivermounted on rollers and having their free ends embedded in the pins ofthe large circle. The small circles are also rotatable and travel attheir points of common tangency with the large circle with a peripheralvelocity equal to that of the large circle. Sliver is fed from the ballsby the action of feed knives which unwind the balls by a given amountwhile the end of the sliver to be combed is held by the pins. After thisoccurs the sliver is lifted from the pins of the large circle onto afeed plate where it straightens out or is set-over. At the stage wherethe rotatinc outer circle reaches its point of common tangency with oneof the inner circles the free end or fringe of the sliver drops backonto the pins of the outer and inner circles and is forced into them bymeans of a dabbing brush. As the outer circle continues to rotate thepins of the two circles separate and the fibres are combed through thepins leaving now two fringes one on the small circle and one on thelarge circle. The long fibres of these fringes are then drawn off thepins by each set of drawing off rollers and fed to a common point toform an output sliver. Since there are two small circles and two fringesare formed at each small circle the output sliver is composed of fibrescoming from four separate points. The noil left on the pins of the smallcircle is subsequently removed by noil knives.

The rate of feeding input sliver to the comb is determined by the amountof set-over resulting from the feeding of the sliver from the balls bythe action of the feed knife. The amount of wool set-over, however, isnot dependent only on the position of the feed knife but is alsoalfected by changes in the tension in the ball of input sliver andvariations in the weight of the sliver per unit length.

It has long been thought that the quality of the output sliver is bestcontrolled by controlling the set-over during the combing operation. Thecommonly accepted criterion for good combing is a constant set-oversince it has been thought that if the set-over is kept constant then thetear ratio (i.e. the ratio of top to noil) will be kept constant.Investigations have, however, shown that the maintenance of a constantsetover would not always produce the desired constant tear ratio.

The feed rate during combing is at present controlled by an operator whoobserves the set-over at regular intervals of say 20 minutes andendeavours to maintain a constant set-over by varying the setting of thefeed knives where necessary, or by an automatic feed knife control3,055,059 Patented Sept. 25, 1962 which varies the position of the knifeat each revolution of the comb to compensate for changes in balltension.

When corrections are made manually, the constancy of the set-overdepends on the subjective assessment of the over-locker and thefrequency with which he attends the comb. Automatic systems, which stilldepend on the overlooker for the initial setting, make a smallcorrection to the feed knives every revolution of the large circle. Themagnitude of this correction presupposes that the input weight isaccurately known, that the drag from the creels remains constant, thatthe tension varies at a known rate and that the tension changes are thesame between sets of balls. Variations produced by the punch box,varying moisture content and standing time .make these conditions rarelysatisfied. In addition neither form of correction makes any attempt tomaintain a constant set-over when rapid tension variations areexperienced during the run in and run out periods of the comb load.Furthermore, neither method of correction is, in fact, sufficientlyaccurate successfully to maintain constant set-over even during normalrunning combing operation in which the setover was inspected and, ifnecessary, corrected every 5 minutes in order to keep it constant, theaverage output weight was found to vary from 116 to 136 drams per minuteor by plus or minus 8% on a range mean of 126 drams per minute. In thesame tests the tear ratio was found to vary between 6.6 and 8.4, avariation of plus or minus 12% on a range mean of 7.5. Thus, in a testwhich was apparently closely controlled, considerable variations both inoutput weight and tear ratio occurred. It is thought that the reason forthese variations, which are short term with respect to the time taken tocomb a load, is the non-homogeneity of the input sliver. For instance,if a thicker than normal sliver is fed into the comb and the set-over ismaintained constant then the output rate will be higher. Furthermore, ifa sliver is too thick then it will become dilficult to draw the fibresthrough the comb and fibre breakage will occur during the combingoperation. This will result in the production of a greater quantity ofnoil and a corresponding decrease in the tear ratio.

In the light of the above investigations it is now proposed according tothis invention to control the input to the comb so as to give asubstantially constant production rate i.e. to give an output sliverhaving a substantially constant number of fibres in cross-section. Inaccordance with the present invention, variations in the average numberof fibres in the cross-section of the output sliver are corrected bysensing the thickness of the sliver and if necessary, in response tothose measurements, correcting the rate at which input sliver is fed tothe comb in order to correct for variations from a predeterminedstandard in the thickness of the output sliver.

More particularly, the invention provides apparatus for maintaining thethickness of output sliver from a Noble comb substantially constant,which apparatus comprises means for detecting variations in thethickness of the output sliver, means operated by the detecting means togenerate electrical signals in response to the detection of variationsfrom a predetermined standard thickness by more than a predeterminedamount, means to average the signals over a finite period and meansactuated by the average of the signals to correct the input of textilematerial to the comb when the average thickness of the output sliverover the finite period varies from the predetermined standard by morethan the predetermined amount. Normally the apparatus will also includemeans operable, after each correction is made, to delay any furthercorrection until such time as the previously corrected sliver reachesthe detecting means. Preferably the means to correct the input oftextile material to the comb comprises an electric motor adapted to varythe position of the feed knives of the comb.

One form of apparatus for carrying the invention into effect comprises apair of spring-loaded conventional tongued and grooved detecting rollerswhich are substituted for the calendar rollers of the can coiler-headwhich receives the output sliver from the comb. Movement of the rollersin response to variations in thickness of the output sliver is caused tooperate a micro-switch which controls the supply of power to the coil ofa relay which in turn is adapted to operate switches controlling thesupply of power to a reversible correcting motor adapted to vary theposition of the feed knives of the comb. The apparatus also incorporatesa timing mechanism for delaying the operation of the correcting motor.

This apparatus will now be more fully described with reference to theaccompanying drawings in which:

FIGURE 1 is a schematic crosssectional view of part of a combing machineshowing the arrangement of the drive from the correcting motor to thefeed knives,

FIGURE 2 is a circuit diagram of the means to supply power to the coilof the contacting meter,

FIGURE 3 is a circuit diagram showing the operation of the contactingmeter and the correcting motor control switches,

FIGURE 4 is a diagram of the time delay circuit, and

FIGURE 5 is a schematic end elevation of the control cam on the timingmotor.

Referring now to FIGURE 1, the numeral 1 represents the large circle ofa Noble comb and 2 represents a conventional feed knife, one end ofwhich is pivoted and the other end of which is forced downward againstthe pressure of a spring 3 by pivoted lever 4 which presses on the topof the push-rod 5 and is adapted to be moved up or down by the collar 6on a column screw 7. The column screw 7 is driven through a gear box 8by means of the reversible correcting motor 9 and a further shaft 10leads from the gear box to another similar knife control unit on theopposite side of the comb.

In FIGURE 2, the switches 11 and 12 represent two contact positions of amicro-switch actuated by movement of the detecting rollers 22 inresponse to variations in thickness of the output sliver, contact 11being made when the sliver is too thick and contact 12 being made whenthe sliver is too thin. Over a period of time the thickness of thesliver will normally vary above and below the desired value causing thecontacts 11 and 12 to be made or broken. The making of the contact 11will cause the condenser 13 to be charged and the making of the contact12 will cause the condenser 14 to be charged. The circuit componentsassociated with these condensers are so chosen that the time constant isabout 20 seconds. Thus at any instant the potential across the terminalsof the meter coil 15 will be a function of the average charge on the twocondensers over the preceding seconds. When this average charge is suchas to indicate a departure from a predetermined value of the thicknessof the output sliver by more than 1%, one or other of the contacts 16,17 on the contacting meter shown in FIGURE 3 will be made.

Provided that the switches on the timing circuit (to be more fullyexplained hereinafter) are in the correct position and provided the combis operating, closing of the contact 16 will cause the relay 18 to beenergised and this will cause the switch 19 to close. Closing of theswitch 19 will energise the relay 20 and this will cause the switch 21to close to supply power to the correcting motor 29 and cause it tooperate in the direction for raising the position of the feed knife 2.Similarly, closing of the meter on the contact 17 will cause the relay23 to be energised and this will close the switch 24 thus energising therelay 25 and closing the switches 26 to cause the motor 9 to rotate inthe opposite direction for lowering the feed knife.

As previously pointed out, after a correction has been made, it isnecessary for a further correction to be delayed until the effect of thefirst correction is detected by the detecting rollers. This is done bythe timing circuit and the timing cam illustrated in FIGURES 4 and 5.The timing cam 27 is driven by a suitable electric motor 28 and isprovided on its periphery with a recess 29 and on its face with anabutment 30. When the timing motor operates the timing cam revolves inthe anticlockwise direction at a speed of one revolution in 22 secondsand when this occurs the switch 31 will close whilst its trigger isopposite the recess 29, in this case for about 2 seconds, and the switch32 will close when its trigger moves off the abutment 30.

The operation of the apparatus is as follows:

With the comb running, output sliver will pass through the detectingrollers and will normally fluctuate above and below a predeterminedthickness causing the microswitch associated with the rollers to closeon one or other of the positions indicated as contacts 11, 12 in FIGURE2 thus charging the condensers 13, 14 and when the average departure ofthe sliver from the predetermined thickness over a 20 second periodexceeds 1% one or other of the contacts 16, 17 on the contacting meterwill be made, depending on whether the average. variation is above orbelow the predetermined thickness. If, say, the sliver is too thick, thecontact 16 will be made thus closing the switch 21 as previouslyexplained and also starting the timing motor 28. This will cause the cam27 to rotate causing the switch 3-1 to close thus supplying power to thecorrecting motor 9 and causing the feed knife to be raised. Thecorrecting motor will continue to operate until the recess 29 on thetiming cam passes the trigger of the switch 31 (in this case, afterabout 2 seconds) when this switch will again open and the power to themotor 9 will be cut off. Rotation of the cam 27 will, however, haveallowed the switch 32 to close so that even if the contact 16 opens thetiming motor will continue to run until a full revolution is completedwhen the switch 32 will be opened by the abutment 30. It, at thecompletion of the cycle, neither of switches 16, 17 are closed thetiming motor will stop with the cam in the position shown in FIGURE 5until such time as the closing of one of those switches initiatesanother cycle. If, on the other hand, one of the switches 16, 17 isclosed at the end of the cycle, then of course the cam 27 will continueto rotate and a further correction will be made.

When the comb is stopped, it is desirable simultaneously to stop theaction of the correcting motor and to place the timing cam in such aposition that a correcting cycle will not be commenced immediately thecomb is restarted. This is done by means of a micro-switch 33 in thecircuit of the contacting meter and a change-over switch 34 in thetiming motor circuit, both of which are actuated by the comb starterswitch, and by a micro-switch 35 in the timing motor circuit actuated bythe abutment 30 on the timing cam. When the comb stops, the micro-switch33 is opened thus preventing the relays 18 and 23 from being energizedand preventing the motor 9 from operating. The changeover switch 34moves to position B and the timing cam continues to rotate until theabutment 30 triggers the micro-switch 35 causing it to open and stop themotor with the cam in such a position that the recess 29 is just on theanti-clockwise side of the trigger of the micro-switch 31. Thus when thecomb is re-started it must run for at least about 20 seconds before acorrection is made.

In an alternative arrangement, thecontacting meter may be replaced by apair of rectifiers adapted to pass current in opposite directions to therelays 18, 23 according to the magnitude and direction of the potentialdifference between the condensors 13, 14.

The above apparatus and method of controlling the combing actionsubstantially reduces long term variations in the weight of outputsliver and produces a relatively constant tear ratio. The detectingdevice used is one which measures, in effect, the number of fibers inthe crosssection of the sliver, since by suitable choice of springpressure it can be made relatively independent of moisture regain sothat in the ideal condition there is obtained an output sliver which isof substantially constant thickness along its length and between combloads. Furthermore, due to the fact that the length of wool set overinto the pins is varied in accordance with variations in the thicknessof the input sliver the occurrence of an abnormally thick sliver doesnot give rise to greatly increased fibre breakage. The tear ratio isthus kept relatively constant as is illustrated by tests which wereconducted with the process controlled and corrected in accordance withthe present invention. In tests similar to those previously quoted, withthe comb controlled, the variation in output weight was reduced tobetween 120 and 125 drarns per minute or plus or minus 2% on a rangemean of 122.5 drains per minute and the variation in tear ratio wasreduced to between 7.3 and 8.1 or plus or minus 5.2% on a range meanratio of 7.7.

Thus it will be seen that, contrary to the present practice, it is notalways desirable to maintain a constant setover but rather should theset-over be varied if necessary to give a constant production rate. Ifthis is done then the output sliver will be more uniform, the fibrebreakage in the comb will be reduced and the tear ratio will be moreconstant.

I claim:

1. Apparatus for controlling the combing of textile fibres in a combingmachine of the type known as a Noble comb, comprising means fordetecting variations from a predetermined standard thickness of theoutput sliver from the comb, means operated by said detecting means togenerate electrical signals corresponding to the detected variations inthickness of the output sliver, means averaging the generated signalsover a finite period, and means actuated by the average of said signalsto vary the input of textile fibres to the comb when the average of thesignals corresponds to an average thickness of the output sliver oversaid finite period varying significantly from said predeterminedstandard thickness.

2. Apparatus as in claim 1, wherein said combing machine has movablefeed knives regulating; the input of textile fibres to the comb, andwherein said means for varying the input of textile fibres to the combincludes a reversible motor adapted to vary the position of said feedknives of the comb.

3. Apparatus as in claim 1, further comprising means operable, followinga variation in the rate of input of textile fibres to the comb, to delayany further variation in the rate of input until such time as theeffected variation exerts an influence on the thickness of the outputsliver influencing said detecting means.

4. Apparatus as in claim 1, wherein said combing machine has movablefeed knives regulating the input of textile fibres to the comb, andwherein said means for varying the input of textile fibres to the combincludes a reversible motor adapted to vary the position of the feedknives of the comb, and further comprising means operable, following avariation in the position of the feed knives, to delay any furthervariation in the position of the feed knives until such time as theeffected variation exerts an influence on the thickness of the outputsliver influencing said detecting means.

References Cited in the file of this patent UNITED STATES PATENTS1,004,092 Sharp Sept. 26, 1911 1,611,539 Layland Dec. 21, 1926 2,465,818Richardson Mar. 29, 1949 2,682,144 Hare June 29, 1954 2,805,449 MartinSept. 10, 1957 FOREIGN PATENTS 212,094 Australia Oct. 24, 1957

